Dipper stick and boom structure



April 28, 1931. SCOTT DIPPER STICK AND BOOM STRUCTURE Filed May 2, 1929I f: I

INVENTOR HARRYE $0077 ATTORNEYS atented Apr. 28, 1931 PATENT OFFICEHARRY E. SCOTT, OF CLEVELAND HEIGHTS, O HIO, ASSIGNOR TO THE THEVt' SHLV'EL COMPANY, OF LORAIN, OHIO, A CORPORATION OF OHIO DIPPER STICK ANDBOOM STRUCTURE Application filed May 2,

The invention disclosed in this application relates generally to dipperstick and boom structures for use in power shovels, and particularly tothe mounti; g of the stick in the boom.

The object of this invention is to improve the mounting of the dipperstick in the boom whereby the stick is permitted free movement in theboom in spite of its position and the various stresses brought to bearupon it, and thereby to improve the driving operation between thedriving elementcarried by the boom and the stick.

Generally speaking, the boom is divided into two side boom portions withthe stick passing between these sides. Mounted between these sides is asuitable driver usually in the form of a pinion which meshes with a rackcarried by the boom, the stick being held with its rack in engagementwith the driver by a portion through which the stick has slidingengagement, and which forms a guide therefor. In another arrangement,this same general structure is employed except that in place of theguiding and holding means between the stick and the driver, as abovespecified, the boom is provided with guides having circular tracksconcentric with the driver and receiving circumt erentially spacedrollers, two in each guide and mounted on roller shafts each of whichhas other rollers engaging the back of the stick and providing ananti-friction means for holding stick and its rack in engagement withthe driver.

The present invention relates specifically to a modified form ofanti-friction mounting between the circular guides, carried by the boomsides and stick, whereby the stick throughout its entire range ofmovement and in spite of its-twists, strains and stresses is free tomove without transmitting such stresses unduly to the rollers or membersengaging in the circular guides. Conversely, the strains and stressesset up by the rollers claims.

in the guides are not transmitted to the stick 1929. Serial No. 359,855.

In the drawings Fig. 1 is a plan view par- .tially in section showingthe boom, stick and guide assembly; Fig. 2 is a side elevation withparts broken away; and Fig. 3 is a plan view of the anti-friction deviceor trolley.

In the drawings the boom comprises two side members 1 and 2 spaced apartat a suitable medial point as indicated at 3, for receiving the stick,its drive and its mounting. At the point in the boom where the stickmounting is to be applied, the two side members 1 and 2 are providedwith bearings indicated at 4 for receiving a transverse driving shaft 5provided, between the members, with a driving pinion 6. The shaft 5 isfurther provided with a driving member or drum 7 adapted to be driven byany suitable means. The pinion 6 is less in width than the space betweenthe side members 1 and 2, and in this space and on each side is thestick guiding means which comprises two opposed and cooperating circularguide members each consisting of a circular back 8, a center hub 9 forreceiving the bearings 4:, and peripheral side face rccesses 10 forreceiving the wheels of the trol ley as will appear. These two guidemembers are secured to their respective side boom members 1 and 2, andhave, at the rear and toward the lower end of the boom, spacer bosses 11one on each member, which meet at the center of the boom and serve toproperly space the two guide members. Suitable aligning openings areprovided through the two guide members in thecenter of the bosses 11 forreceiving a tie rod or bolt 12 holding them in axial alignment.

From the foregoing it will be seen that there are opposed guidingmembers mounted concentrically about the axis of the driving shaft andits pinion, and secured to the boom sides so that the circular trackways in these guide members are concentric with the driving pinion andits shaft.

Engaging the pinion 6 is a rock 13 carried by the stick 14 which isusually provided with a shovel, excavator or scoop at its lower end.

The foregoing sets forth a structure which is now familiar to thoseskilled in the art and does not form any specific part of the inventionexcept in so far as it enters into the combination. A specificembodiment of the mechanism which'forms the basis of the invention, willnow be described.

In order to holdthe stick 14 in engagement with the pinion 6 and topermit it to slide freely throughout its range of movement. a suitableaccommodating trolley or ant ifriction backing device is provided and itconsists of a cross-shaped frame including the transverse tubular member15 and the longitudinal member 16, these two members crossing atsubstantially their center. Mounted in the tubular member 15 is a rollershaft 17 carrying at its outer end rollers 18 adapted to engage in thecircular track ways 10 of the guiding members. The longitudinal member16 is provided near both of its ends with transverse slots 19 extendingupwardly from the bottom and receiving squared portions 20 of shafts 21extending out at both sides. Each of the four end extensions thusformed, is provided with a roller 22. Engaging each squared portion 20at the center is a screw 23 held in any suitable position by a check-nut24. It is obvious that these adjusting screws when moved downward willengage the squared portions 20 of the shafts and take up any undesirableback lash between the track ways 10 and the stick 14. The center shaft17 is held in place by a suitable set screw arrangement 25.

The four rollers 22 carried by the end shafts engage the back side ofthe stick and hold the rack 13 in engagement with the driving pinion,while the two rollers 18 bear in the annular recesses 10 for thepurpose.

It will be seen from the foregoing that the anti-friction trolleyarrangement herein described will provide a backing means for the stickand its rack, and will permit free movement of the stick throughout itsentire range without the transmission of undue strains and stresses.

Having described my invention, I claim:

1. A trolley of the class described and comprising a cruciform frame,end rollers disposed one on each side of each end of the longitudinalframe member, and side rollers disposed at the ends of the transverseframe member, with portions overlying the end rollers.

2. In combination with a pair of spaced guides having circular trackwaysand a dipper stick extending between said guides, a trolley comprisinga. frame and idler rollers carried thereby, said rollers including apair of aligned side rollers bearing in said annular trackways, andpaired end rollers mounted to move on axes ahead and behind that of saidside rollers, and bearing against said dipper stick.

3. In combination with a pair of spaced guides having circular trackwaysand a dipper stick extending between said guides, a trolley comprising aframe and idler rollers carried thereby, said rollers including a pairof side rollers bearing in said annular trackways, and endrollersmounted to move on axes ahead and behind that of said side rollers andbearing against said dipper stick, and means for adjusting one of saidaxes in said frame to adjust the said bearing of a. corresponding rollerand hence to effect adjustment of the said bearings of the otherrollers.

4. In combination with a pair of spaced guides having circular trackwaysand a dipper stick extending between said guides, a trolley comprisinga. frame and idler rollers carried thereby, said rollers including apair of side rollers located on a central axis and bearing in saidannular trackways, and pairs of end rollers located on axes ahead andbehind that of the side rollers and bearing against said dipper stick,and means provid ing for angular movement of one of said axes in saidframe to allow the said bearings of its rollers to have differentialrelation.

5. In combination with a pair of spaced guides having circular trackwaysand a dipper stick extending between said guides, a trolley comprising aframe and idler rollers carried thereby. said rollers including a pairof side rollers located on a central axis and bearing in said annulartrackways, and pairs of end rollers located on axes ahead and behindthat of the side rollers, and bearing against said dipper stick, meansfor adjust ing one of said axes in said frame to adjust bearing of itscorresponding rollers, and means providing for angular movement of oneof said axes in said frame to allow said bearings of its rollers to havedifferential relation.

In testimony whereof I hereby affix my signature.

HARRY E. SCOTT.

